Such a transverse element is generally known, and is designed for application in a drive belt for a continuously variable transmission. Such a drive belt comprises two bundles of endless bands being shaped like a closed loop, which function as carriers of a number of transverse elements. The transverse elements are continuously arranged along the entire length of the bands, in order for them to be able to transmit forces which are related to a movement of the drive belt during operation.
The transverse element is on both sides provided with recesses for at least partially receiving the bundles of bands. A portion of the inner surface of a recess forms a supporting surface for supporting a bundle of bands.
Furthermore, for the purpose of contact between the transverse elements and the pulley sheaves of the continuously variable transmission, the transverse elements on both sides are provided with pulley sheave contact surfaces which are divergent in the direction of the supporting surfaces.
A supporting surface is on the one side connected to a pulley sheave contact surface and on the other side to a side surface of a neck portion of the transverse element, through a transition region. The neck portion comprises the portion of the transverse element being situated between the recesses. Besides the neck portion, the transverse element comprises an inner portion and an outer portion, wherein the inner portion comprises the supporting surfaces and the pulley sheave contact surfaces. On application of the transverse element in a drive belt, the transverse element is positioned such that the inner portion is located at the inner circumference of the drive belt and the outer portion is located at the outer circumference of the drive belt.
A projection is arranged on a front surface of the outer portion, while a hole is arranged in a back surface of the outer portion. The positions and the dimensions of the projection and the hole are adapted to each other in such a way that the projection of a transverse element can be received by the hole of a subsequent transverse element. An important function of the projections and the holes is preventing a mutual displacement in transverse direction of subsequent transverse elements which are part of a drive belt.
The dimensions of the outer portion are also determined by the projection and the hole. The fact is, the projection and the hole are preferably formed in the outer portion with the help of a die and a corresponding mould during a manufacturing process for forming the transverse element, like the punching process. In the process, a certain surface surrounding the projection and the hole, which in this case is called the fixture surface, is necessary for obtaining a sufficiently strong die and mould and for sufficiently supporting the transverse element during the formation of the projection and the hole. Moreover, the transverse element needs to posses a certain strength being suitable for utilisation thereof in the drive belt.
As already noted in the above, the transverse element is designed for application in a drive belt for a continuously variable transmission. The continuously variable transmission can for example be designed to be build into a motor vehicle. It is therefore desired that the weight of the transverse element is a low as possible, while the transverse element has to be sufficiently strong to absorb the forces which occur during operation of the continuously variable transmission.
The present invention provides for weight-saving relative to the known transverse element. For this purpose, at least a portion of the neck portion of a transverse element according to the invention tapers towards the supporting surfaces.
The tapered layout of the neck portion results in the outer portion and the inner portion being able to be smaller, whereby the weight of the transverse element is lower relative to a known transverse element being provided with a neck portion, the side surfaces of which extend substantially parallel relative to each other. After all, the tapered layout is such that the neck portion is relatively large at the side of the outer portion. As a result, in the transverse element according to the invention, the projection and the hole can be displaced in the direction of the neck portion, relative to the known transverse element. The fixture surface being situated around the projection and the hole, which amongst others is necessary for being able to obtain a sufficiently strong die and mould and for being able to sufficiently support the transverse element during the formation of the projection and the hole, can then also be displaced in the direction of the neck portion, so that a portion of the outer portion can be removed. In order to guarantee the stability of the transverse element, a portion of the inner portion needs then also to be removed. The weight-saving is achieved, because the portion which is added to the neck portion is smaller than the total portion which can be removed at the outer portion and the inner portion.
It is noted that in JP04083941 a transverse element and a bundle of bands are being disclosed, wherein an angle is defined between a position of a standing side of the bundle of bands when this is in a normal position on the supporting surface of the transverse element, and a position of the standing side when the bundle of bands has undergone an angular displacement relative to the normal position. Alternatively, such angular displacement can be described as a rotation of the transverse element about the centre of its projection relative to the bundle of bands. In order to reduce the chance of occurrence of linear contact between a relatively sharp portion of the bundle of bands and the side surface of the neck portion of the transverse element in case of an angular displacement of the bundle of bands, the position of the side surface is adapted. The position is chosen to be such that on an angular displacement in transverse direction of the bundle of bands, contact between a standing side of the bundle of bands and the side surface of the neck portion of the transverse element can take place through a plane, whereby the chance of damage of the side surface is reduced. In this position, the side surface is at an angle with an imaginary line extending perpendicular relative to the supporting surface, which angle equals the angle being present between the bands at a maximum angular displacement in transverse direction and the supporting surface. Generally, this latter angle is approximately 1° to 2°. It will be clear that the maximum angular displacement of the bundle of bands is determined by the width and the height of the bundle of bands and the width and the height of the recess.